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RE: Question about precision.

  • To: mathgroup at smc.vnet.net
  • Subject: [mg38416] RE: [mg38405] Question about precision.
  • From: "Florian Jaccard" <jaccardf at eicn.ch>
  • Date: Sat, 14 Dec 2002 03:19:55 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Hello !

I'm not an expert... But here a easy way fo obtain 50 significant numbers :

In[1]:=
Sqrt[1.3`50]

Out[1]=
1.14017542509913797913604902556675447907600531091641

In[2]:=
% %//FullForm

Out[2]//FullForm=
1.2999999999999999999999999999999999999999999999999999999999999694004`50

Meilleures salutations

Florian Jaccard


-----Message d'origine-----
De : Wen-Feng Hsiao [mailto:wfhsiao at libra.seed.net.tw]
Envoyé : ven., 13. décembre 2002 10:19
À : mathgroup at smc.vnet.net
Objet : [mg38405] Question about precision.


Dear experts,

I try to find the square root of 1.3, but obtain an not so correct
answer. Could someone point me how to do? My trials are the
followings.

In[28]:=
Sqrt[1.3]

Out[28]=
1.14018

In[29]:=
Precision[Sqrt[1.3]]

Out[29]=
16

In[30]:=
N[Sqrt[1.3], 50]

Out[30]=
1.14018

In[31]:=
1.14018*1.14018

Out[31]=
1.30001

The more precise answer should be
In[32]:=
1.140175425*1.140175425

Out[32]=
1.3

Thanks for your help!

Wen-Feng Hsiao




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